The present invention relates to new vegetable oils, in particular oils from sunflower, soybean, rape, corn etc., which are particularly suitable for applications in which the oil is heated. The invention further relates to the use of the. oil, to seeds containing the oil and to by-products of the process of extracting the oil.
Vegetable fats and oils used for deep frying, baking and other applications in the food industry require high thermostability. Partially hydrogenated oils, palm oil and high oleic vegetable oils are commonly used to fulfill this requirement. However, partially hydrogenated fats contain trans isomers of fatty acids that are considered undesirable from a nutritional point of view.
Fats and oils are triesters of glycerol with fatty acids and are called triglycerides or triacylglycerols (herein also identified as xe2x80x9cTAG""sxe2x80x9d). The three fatty acids within a triacylglycerol can be the same or different and may be either saturated or unsaturated. The physical properties of a triacylglycerol depend on its fatty acid composition.
Palm oil and partially hydrogenated fats contain high levels of saturated fatty acids at position sn-2 of their triacylglycerols as compared with most vegetable oils like soybean, sunflower and rape. The location of saturated fatty acids in the sn-2 position has been suggested to be responsible for the atherogenic effects of these acids (Renaud et al., J. Nutr. 125:229-237 (1995)). The use for food applications should therefore be avoided.
In view of the above, there is a need for new natural oils that have higher thermostability and also avoid the excess presence of saturated fatty acids in the sn-2 position of the TAG.
To achieve this the present invention provides a sunflower oil, which is extracted from sunflower seeds and in which at least 12% of the triacylglycerol species that constitute the oil have the general formula SMS and at least 25% of triacylglycerol species have the general formula SMM, wherein the formula gives from left to right the first, second and third fatty acid in the triacylglycerol and S represents a saturated fatty acid and M represents a monoenoic fatty acid. It was surprisingly found that oils of this type have excellent thermostability and also have a lower than 8% of saturated fatty acids content on the sn-2 TAG position.